function Map(){
	this.obj = {};
}
Map.prototype = {
	constructor:Map,
	put:function(key,value){
		this.obj[key] = value;
	},
	remove:function(key){
		if(this.obj[key]||this.obj[key]===0||this.obj[key]===false){
			delete this.obj[key];
		}
	},
	size:function(){
		var c = 0;
		for(attr in this.obj){
			c++;
		}
		return c;
		},
	get:function(key){
		if(this.obj[key]||this.obj[key]===0||this.obj[key]===false){
			return this.obj[key];
		}else{
			return null;
		}
		
	},
	eachMap:function(fn){
		for(attr in this.obj){
			fn(attr,this.obj[attr]);
		}
	}	
}